This invention is in the field of an implantable vaso-occlusive device. In particular, the invention includes deployable devices such as coils in which the round wire making up the coil is flattened in at least one area. The coil efficiently self-forms into a three-dimensional shape when deployed into a body cavity. The flattened areas induce the three-dimensional formation in the desired directions and shapes. Methods of producing and using the vaso-occlusive coils are also provided.
Vaso-occlusion devices are surgical implements or implants that are placed within the vasculature of the human body, typically via a catheter, either to block the flow of blood through a vessel making up that portion of the vasculature through the formation of an embolus or to form such an embolus within an aneurysm stemming from the vessel. One widely used vaso-occlusive device is a helical wire coil having windings which may be dimensioned to engage the walls of the vessels. Other less stiff helically coiled devices have been described, as well as those involving woven braids.
For instance, U.S. Pat. No. 4,994,069, to Ritchart et al., describes a vaso-occlusive coil that assumes a linear helical configuration when stretched and a folded, convoluted configuration when relaxed. The stretched condition is used in placing the coil at the desired site (by its passage through the catheter) and the coil assumes a relaxed configurationxe2x80x94which is better suited to occlude the vesselxe2x80x94once the device is so placed. Ritchart et al. describes a variety of shapes. The secondary shapes of the disclosed coils include xe2x80x9cflowerxe2x80x9d shapes and double vortices. A random shape is described, as well.
Vaso-occlusive coils having attached fibrous elements in a variety of secondary shapes are shown in U.S. Pat. No. 5,304,194, to Chee et al. Chee et al. describes a helically wound device having a secondary shape in which the fibrous elements extend in a sinusoidal fashion down the length of the coil. These coils, as with Ritchart et al., are produced in such a way that they will pass through the lumen of a catheter in a generally straight configuration and, when released from the catheter, form a relaxed or folded shape in the lumen or cavity chosen within the human body. The fibrous elements shown in Chee et al. enhance the ability of the coil to fill space within the vasculature and to facilitate formation of embolus and subsequent allied tissue.
Vaso-occlusive coils having little or no inherent secondary shape have also been described. For instance, co-owned U.S. Pat. Nos. 5,690,666 and 5,826,587 by Berenstein et al., describes coils having little or no shape after introduction into the vascular space.
There are a variety of ways of discharging shaped coils and linear coils into the human vasculature. In addition to those patents which apparently describe only the physical pushing of a coil out into the vasculature (e.g., Ritchart et al.), there are a number of other ways to release the coil at a specifically chosen time and site. U.S. Pat. No. 5,354,295 and its parent, U.S. Pat. No. 5,122,136, both to Guglielmi et al., describe an electrolytically detachable embolic device.
A variety of mechanically detachable devices are also known. For instance, U.S. Pat. No. 5,234,437, to Sepetka, shows a method of unscrewing a helically wound coil from a pusher having interlocking surfaces. U.S. Pat. No. 5,250,071, to Palermo, shows an embolic coil assembly using interlocking clasps mounted both on the pusher and on the embolic coil. U.S. Pat. No. 5,261,916, to Engelson, shows a detachable pusher-vaso-occlusive coil assembly having an interlocking ball and keyway-type coupling. U.S. Pat. No. 5,304,195, to Twyford et al., shows a pusher-vaso-occlusive coil assembly having an affixed, proximally extending wire carrying a ball on its proximal end and a pusher having a similar end. The two ends are interlocked and disengage when expelled from the distal tip of the catheter. U.S. Pat. No. 5,312,415, to Palermo, also shows a method for discharging numerous coils from a single pusher by use of a guidewire which has a section capable of interconnecting with the interior of the helically wound coil. U.S. Pat. No. 5,350,397, to Palermo et al., shows a pusher having a throat at its distal end and a pusher through its axis. The pusher sheath will hold onto the end of an embolic coil and will then be released upon pushing the axially placed pusher wire against the member found on the proximal end of the vaso-occlusive coil.
None of these documents disclose coils having selectively flattened portions to enhance coil formation in certain directions.
Thus, this invention includes novel vaso-occlusive devices having flattened surfaces methods of using and making these devices
In one aspect, the present invention includes a vaso-occlusive device comprising an elongated wire having a round cross-section wound into a first configuration of a helical linear coil having a longitudinal axis and two ends, wherein the helical linear coil self-forms into a second configuration when deployed into a body cavity and wherein selected portions of the wire wound into the helical linear coil have been flattened such that the cross-section of the wire is not round. The flattened portions allow for efficient coil formation. Thus, the flattened portions of the wire may form a pattern over the longitudinal axis of the coil, for example a striped or helical pattern or, alternatively, may appear to be xe2x80x9crandom,xe2x80x9d so long as they are positioned to promote coil formation in the desired directions and shapes. The devices described herein may further include additional filamentary material attached to the coil; a deployment tip (e.g. mechanically or electrolytically detachable ends) attached to at least one of the two ends of the coil.
The selectively flattened devices described herein can be produced, for example, by rolling the linear coil against a high strength material (e.g. mandrel) or by using a swage on the linear coil.
Also included in the present invention is a method of occluding a body cavity comprising introducing any of the vaso-occlusive devices described herein into the body cavity (e.g. an aneurysm).
These and other embodiments of the subject invention will readily occur to those of skill in the art in light of the disclosure herein.